import java.math.*;

class Animal{
    public void eat(){
        System.out.println("吃东西");
    }
}

class Cat extends Animal{
    @Override
    public void eat() {
        System.out.println("吃猫粮");
    }

}

interface AA {
    void funcA();
}

class BB implements AA{

    @Override
    public void funcA() {
        System.out.println("funcA()");
    }
}

public class Test {

    public static void eatAnimal(Animal animal){
        animal.eat();
    }

    public static void main(String[] args) {
        Animal animal = new Cat();
        eatAnimal(animal);
    }

    /*public static final double e = 1e-6;

    public static void main(String[] args) {
        double x = 3.14 / 6;
        boolean flag = true;
        int cnt = 0;
        for (int i = 3; flag; i+=2,cnt++){
            int total = 1;

            for (int j = 1; j <= i; j++){
                total *= j;
            }

        }
    }*/
}
